FIELD ENHANCEMENT 2 Studying Forest Layers OBJECTIVES NUTSHELL In this lesson, students observe the structural Upon completion of this lesson, students will layers of a forest and draw a color-coded picture. be able to: They also embark on two exploration activities to • Identify the structural layers in a forest. discover which animals can be found in each of • Describe wildlife that can be found in each the forest layers. of the layers of a forest. BACKGROUND SUBJECT AREAS Forests vary in their composition (species Arts, Science present) and their structure (how species are arranged). Forests may LESSON/ACTIVITY TIME Forest Layers have any combination • Total Lesson Time: 75 minutes • Overstory of the following layers: • Time Breakdown: overstory, understory • Understory which includes trees, Introduction...........10 minutes - Trees shrubs, and forbs, and Activity 1 ...............30 minutes - Shrubs litter. A mixed forest, for Activity 2 ...............10 minutes - Forbs example, may contain Activity 3 ...............10 minutes • Litter all of the layers. A pine Conclusion............15 minutes plantation may only have TEACHING SITE an overstory, forb layer, and litter layer. Each layer contains its own set of plant species and A forested area that contains five layers provides food and shelter to wildlife. (overstory, understory, shrub, forb, litter) is preferable. The overstory is above all the layers and is made up of mature trees. Tree species CLASSROOM LESSON commonly found in the overstory include white CONNECTIONS and red pine, sugar and red maple, white ash, This lesson ties closely with Classroom red and white oak, and trembling aspen. Animals Lesson 2, What Makes a Forest? that use the overstory of a forest include blue jays, owls, orioles, hawks, woodpeckers, eagles, squirrels, crows, turkeys, and porcupines. The understory may contain a tree, shrub, and forb layer. Trees in this layer are usually immature. When a mature tree from the overstory dies, some of the immature trees may grow taller and become part of the overstory. The understory also contains smaller trees like choke or pin cherry, serviceberry, red cedar, ironwood, and musclewood. 170 Field Enhancement 2: Studying Forest Layers LEAF Guide • 5-6 UNIT VOCABULARY MATERIALS LIST FOR EACH STUDENT Forb Layer: Layer of the understory containing • Copy of Student Page 1, Forest Layers non-woody plants. • Five different colored pencils Litter Layer: Surface layer of the forest floor • Clipboard or other writing surface composed of leaves, twigs, needles, etc., with FOR EVERY 3 TO 4 STUDENTS minimal decomposition. • Bug boxes or magnifying lenses (optional) Overstory: The uppermost trees in a forest. • One white paper plate Shrub Layer: Layer of the understory FOR THE CLASS containing woody plants with multiple stems. • Copy of Student Page 2, Forest Layers Understory: Forest vegetation present Example Page under the overstory, which can include trees, shrubs, and forbs. TEACHER PREPARATION • Visit the teaching site in advance and choose boundaries for your students to work within. These trees are shade-tolerant. This means that they are able to grow well even when the • Choose an area on the site where your trees growing above them block most of the students can sit down and observe forest light. Animals in the tree layer of the understory layers independently. are similar to those in the overstory. • Choose an area where small groups of students can sit on the ground and study The shrub layer occupies the space between leaf litter. the understory trees and the forb layer. Woody • Choose a trail on which to take a short walk plants like raspberry, maple-leaved viburnum, to look for wildlife or evidence of wildlife. dogwood, and witch hazel are found here. This layer provides food and habitat for a SAFETY PRECAUTIONS variety of wildlife like squirrels and deer. Birds Visit the teaching site ahead of time to locate common to the shrub layer in Wisconsin forests any hazards such as hanging branches, include grouse, robins, chickadees, warblers, protruding tree roots, holes, poison ivy, sparrows, finches, cardinals, mourning doves, etc. Encourage students to walk, not run, and grosbeaks. at all times. The next layer of the understory is the forb layer. Small herbaceous (fleshy, not woody-stemmed) plants like bracken fern, wild columbine, pink The litter layer contains fallen leaves, branches, lady slipper, and common blue violet grow here. needles, and other organic matter. Items in this Chipmunks, snakes, toads, mice, moles, grouse, layer are easily recognizable. They are starting turkeys, rabbits, insects, turtles, and spiders all to break apart but have not begun to decompose. use this layer. Critters commonly found in this layer are centipedes, millipedes, ants, beetles, worms, snails, slugs, maggots, spiders, and pill bugs. LEAF Guide • 5-6 UNIT Field Enhancement 2: Studying Forest Layers 171 Although the plant species in each forest layer 5. The next layer is composed of the understory are more clearly defined, wildlife frequently use trees. Ask your students to look around for more than one or all the layers of a forest. For trees whose crowns fit underneath the crowns example, we commonly find squirrels leaping of larger trees. Explain that these trees can along the forest floor, as well as from branch to tolerate a lot of shade. They are either young branch up in the treetops. In fact, squirrels make trees or species that do not get as big as the their nests in the branches of trees. Wild turkeys other trees around them. Tell your students eat nuts and insects from the leaf litter; they that these trees make up part of the understory. also eat food found in the forb and shrub layer. The shrub layer and forb layer are also part of In addition, they roost on branches in the the understory with the trees. understory or overstory. 6. Finally, ask your students to look directly PROCEDURE overhead at the tallest trees in the forest. Explain that this layer is called the overstory. INTRODUCTION These trees dominate the forest. Very little 1. Take students to the forested area you have light passes through their branches to the chosen for exploration. forest floor. Tell your students that when one 2. Have students sit in a circle on the ground in of the trees in the overstory dies, a tree in the forest. Explain that the forest is comprised the understory may have an opportunity to of different layers. Ask them to pick up a become a dominant tree. handful of debris from the ground. Ask what NOTE: If your forested area does not contain they see in this debris. (Leaves, twigs, all five layers, explain all the layers but modify needles, nuts, moss, and other decaying the activity to accommodate your site. plant material.) Explain that this layer, called leaf litter, is where things in the forest ACTIVITY 1 are recycled. Decomposers like fungi, worms, 1. Hand each student a copy of Student Page beetles, and ants break down dead plant 1, Forest Layers, a clipboard, and a set of material and return the nutrients to the soil colored pencils. Explain that they will have so that living plants can use them. time to sit alone and observe the different layers in the forest. Tell them they need to 3. Next, ask someone to point to a non-woody make a drawing of what they observe. The plant that is growing close to the ground. drawing should contain the plants found in Explain that small herbaceous (fleshy, not each of the layers. Ask them to choose a woody-stemmed) plants like these make up different color to draw each of the layers. For the forb layer of the forest. This layer provides example, the forb layer may be purple, the shelter to animals like snakes, toads, rabbits, shrub layer orange, and so on. Tell them that insects, turtles, and spiders. after their drawings are complete, they should 4. Ask your students to look around and spot a fill in the name of each layer on the blank woody-stemmed bush or a sapling. Explain provided. It is important that the drawings that these types of plants make up the shrub show detail and are complete. You can show layer of the forest. Squirrels, deer, and many Student Page 2, Forest Layers Example types of birds benefit from the cover and food Page, as an example. these plants offer. 172 Field Enhancement 2: Studying Forest Layers LEAF Guide • 5-6 UNIT 2. After you have given the directions, explain them to get a closer look. Show your students the boundaries you have chosen for this where to make note of any animals they find lesson. Then ask your students to spread on their worksheet. (There are examples of out within the boundaries and find their own wildlife for all the layers listed along the edge place to sit and work. Give your students time of the student page.) to draw, then bring them back together to sit in a circle. 2. After you have explained the activity, ask the groups to spread out and begin working. As 3. During Activities 2 and 3, your students will they work, walk around and check on their add more information to their worksheets. progress. If anyone has trouble with finding Before continuing, quickly check to be sure critters in the leaf litter, have them put their that everyone drew five layers. Ask your group sample back, move to another location, and to put their drawings on the ground in front of try again. them. As you walk around and check their work, ask the group to point to the overstory 3. When all the groups have had time to work, layer as well as the understory trees, shrub, remind them to put the leaf litter and critters forb, and leaf litter layers.